This invention relates to an agricultural implement and method, more particualrly to an attachment for tractors and the like for mechanically pulling woody plants having extensive root systems from the ground, and even more specifically for extraction of the extended tap root of the Huisache and other plants.
Improved pastureland may become heavily invaded by the woody, throny, Huisache and Mesquite plants which grow generally vertically with a long tap root extending into the ground. The Huisache and Mesquite create not only problems for grazing animals, but also rob the soil of precious moisture necessary for the proper growth of pastureland grasses. Further, the Huisache is thickly branched and often shades out the grass. All of these problems are amplified in regions where there is minimal rainfall or where drought conditions exist.
There have been a number of methods and apparatuses utilized to remove or eliminate the Huisache and Mesquite plants, all of which are costly either in terms of money, labor, or environmental impact. One current method of removal employs the use of a D-8 caterpillar tractor with a root plow. The plow digs into the ground and severs the tap root beneath ground level, the plow continues to disturb the soil and the plant is turned over. A root rake then is employed to rake and stack the plants for subsequent burning. The technique is costly monetarily and results in excessive damage to the grass turf.
Another technique used is hand or mechanical grubbing. A grubbing hoe or small grubbing plow is used to cut the tap root below the ground and may be only effectively used when the plants are small and the soil is sufficiently moist. Unfortunately, the tap root is usually not fully extracted and the plant later reemerges thicker and more troublesome. The hand grubbing technique is incredibly time and labor intensive and must be done when the plants are small. Mechanical grubbing greatly disturbs the soil, and, like hand grubbing, leaves root remnants to re-emerge. Oftentimes acreage is heavily infested with the Huisache plant at the time it is converted to pastureland, making the hand grubbing technique unacceptable.
Yet another method which is gaining popularity is the use of herbicides. This technique has the disadvantages of being monetarily costly and environmentally unsatisfactory.
While many brush and tree pullers have been developed, none has been as suitable as the present invention for use in extracting the Huisache and Mesquite plants. U.S. Pat. No. 2,505,923 discloses a tree or brush puller with gripping jaws which are engagable around a tree trunk. The tractor is driven forward and a horizontal pulling force is applied to the tree. With the Huisache plant use of the puller of U.S. Pat. No. 2,505,923 is not effective because there is no initial vertical lift on the plant to initiate the dislodgement of the long tap root found in the Huisache plant. Further, the jaws of the '923 device generally apply clamping forces to the sides of the tree, or in a direction perpendicular to the movement of the pulling tractor. This arrangement of forces results in considerable slippage of the jaws upwardly along the sides of the tree during removal.
Another tree or bush pulling apparatus is shown in U.S. Pat. No. 3,057,599. With such an apparatus the to be removed tree is grasped by gripping jaws and a hydraulic cylinder is actuated to cause linkages to lift the tree vertically. The arms of the apparatus of U.S. Pat. No. 3,057,599 are pivotally attached to the lower frame of the tractor and the hydraulic cylinder must exert sufficient force to lift the tree creating an opposing force tending to lift the front end of the tractor.
Many other pullers are known but they are much more complicated, costly to build, and require excessive maintenance. Examples of such pullers may be seen in the following U.S. Pat. Nos.: 2,535,099; 2,535,054; 3,427,640; 3,208,726; 3,311,350; 4,706,935; 3,823,916; 3,958,613; 2,436,510; 4,067,369; and 3,802,663. Despite the existence of these devices and such efforts aimed at extraction of trees and brush, the problems of removing the Huisache and Mesquite plants have continued to plague farmers and ranchers.
The present invention offers an inexpensive and easy-to-use solution to this long-standing problem.